In Bemidji, a research site reveals secrets of an oil spill

  • Article by: DAVID SHAFFER , Star Tribune
  • Updated: June 15, 2014 - 7:12 PM

The site of a pipeline rupture has become a research center unlike any other in the world.

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At the site of 1979 spill near Bemidji, scientists have dotted the landscape with bore holes to study of the lingering underground pollution. Here, crews bore 27 feet below the surface to survey the groundwater for oil from the 1979 spill.

Photo: Brian Peterson, Star Tribune

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PINEWOOD, MINN. -- The rusty, 1950s-era drilling rig bored noisily in the sandy soil, stopping at a depth of 27 feet. As workers lifted out the spiral bit, a whiff of petroleum drifted up the hole. “That’s some Bemidji crude oil,” said Jared Trost, a hydrologist for the U.S. Geological Survey in charge of the rig.

Thousands of gallons of crude oil gurgle underground at this spot off a gravel road 12 miles northwest of Bemidji, Minn. It isn’t a new shale oil discovery.

The crude oil is the stubborn remnant of a massive 1979 pipeline rupture. Over the past three decades, this site has become a science center unlike any other in the world. Using data collected mostly from bore holes, scientists have produced a gusher of research discoveries, including some that have influenced U.S. pollution cleanup policy.

“We are trying to take advantage of a bad situation and learn what we can from it,” said Mindy Erickson, a USGS hydrologist based in Mounds View who manages the research site.

The site is slightly larger than a football field, has no buildings and consists mainly of hundreds of wells drilled for sampling and other research. The pipeline that ruptured, spilling nearly 450,000 gallons of crude oil in 1979, runs through the middle of it.

Much of the spilled oil was cleaned up in the weeks after the accident, but techniques used 35 years ago left about 100,000 gallons in the ground.

“Today, you wouldn’t walk away with that much oil in the ground — that just wouldn’t happen,” said Scott Lounsbury, senior environmental manager for Enbridge Energy, the Calgary-based pipeline owner.

Enbridge didn’t actually walk away. It helped launch a research project that’s still going 31 years later.

“It is a unique site,” said Bruce Bauman, research program coordinator for the American Petroleum Institute, a Washington-based trade group that supports spill research. “It is certainly the most studied site in the world.”

Americans consume 18 million barrels of oil per day. It moves mostly by pipelines, which have 350 accidents a year, spilling more than 50,000 barrels of hazardous liquids. Cleaning up oil spills is expensive, and even as techniques improve, it’s rarely possible to recover every drop that seeps underground.

Learning from nature

Pollution control experts once doubted that subsurface microbes could break down oil because of the lack of oxygen. But scientists working at the Bemidji site published scientific studies in the 1990s that showed otherwise.

“Those results got nationwide attention,” said Barbara Bekins, a USGS research hydrologist based in Menlo Park, Calif., who coordinates research at the Bemidji site.

As a result, “natural attenuation” was recognized as a cost-effective way to remove underground pollution, especially from urban gas station tanks where digging up blocks of property isn’t an option.

Scientists on the Bemidji Crude Oil Research Project also have made discoveries about the spread of pollution “plumes” underground, pioneered ways to measure natural breakdown of oil and learned about how petroleum-eating bacteria work.

Research at the site has shown that bugs rapidly eat toxic, water-soluble compounds such as toluene and benzene. The spread of such compounds in the site’s water table has halted about 500 feet of the spill. “Toluene is 100 percent gone,” Bekins added.

Much of the remaining oil floats atop the water table, about 2-feet thick. But it hasn’t moved far, suggesting that even a major oil spill doesn’t necessarily pollute an entire aquifer. That’s been a worry about the massive Ogallala aquifer in Nebraska, where antipipeline activists oppose building TransCanada’s proposed Keystone XL crude oil pipeline.

“The position that … one pipeline release to a sandy aquifer is going to destroy the aquifer forever, the science doesn’t back that up,” said Paul Meneghini, a senior environmental manager for Enbridge.

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  • A rust-coated drilling rig, which dates to 1956, has bored dozens of test wells at the site of a 1979 spill near Bemidji, Minn. It has helped scientists produce research discoveries, including some that have influenced U.S. pollution cleanup policy.

  • USGS hydrologist Jared Trost stood among the many bore holes scientists use to study the movement and breakdown of crude oil.

  • What they found underground

    What scientists have found underground

    Scientists have published hundreds of articles in scientific journals using data collected at the Bemidji oil spill site. Here are the key discoveries over three decades.

    • Underground bacteria feed on oil and degrade it even in the absence of oxygen. Iron in the soil helps this process.

    • Bacteria eat petroleum fast enough to keep a subsurface plume of contamination from spreading. But microbes speedily devour only some petroleum compounds such as toluene, a toxic solvent.

    • If oil seeps into a water table, it can float there for decades.

    • Trying to suction oil from the water table via wells can produce large quantities of oil-tainted water, leaving things no better.

    • Crude oil compounds in a wetland got chewed up quickly by the rich microbe life.

    • When bacteria eat crude oil, they emit a gas that converts to carbon dioxide as it works though the soil. Gas-measuring devices on the surface can reveal the pace of the breakdown of subsurface oil.

    • Bugs that chew up buried crude oil sometimes free up arsenic, a toxic heavy metal. Scientists are studying whether other minerals react with arsenic to hold it in place.

    • Studying the genetic fingerprint of bacteria shows which strains work hardest at degrading petroleum.

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